Media captionPaul Dacre: "Hugh Grant has spent his life invading his own privacy"

The Daily Mail's editor was aware the paper was using private detectives but not of the extent to which it was doing so, the Leveson Inquiry has heard.

Paul Dacre, the last Fleet Street editor to go before the inquiry, said this practice of accessing information used to be commonplace in the industry.

"Everybody, every newspaper" had been using private detective Steve Whittamore at one stage, he said.

In 2005, Whittamore was convicted of illegally accessing data.

Mr Dacre, who also holds the post of editor-in-chief of Associated Newspapers, the paper's publishers, admitted he was aware that the Daily Mail had been using Whittamore before 2006.

"We didn't realise what they were doing was illegal," he said.

"There was a very hazy understanding of how the Data Protection Act worked and this was seen as a quick way of obtaining phone numbers and addresses to corroborate stories," he said.

Earlier in the inquiry, Mail on Sunday editor Peter Wright said his paper continued to use Whittamore for 18 months after a police investigation into the unlawful trading of personal information.

Mr Dacre, however, said he had sought written assurances from Whittamore that he was acting within the law and, in 2007, he banned the use of all "Whittamore inquiry agencies".

He also told the inquiry that newspapers should have the latitude to look into the lives of erring celebrities, such as celebrity chefs, sportsmen and others who made money revealing their lives to the public.

'Standards ombudsman'

Mr Dacre said he had never placed a story in the newspaper that he knew had come from phone hacking and was convinced it did not happen.

"I know of no cases of phone hacking," he said. "Having conducted a major internal inquiry, I am as convinced as I can be that there is no phone hacking on the Daily Mail.

"I don't make that statement lightly. And no editor, the editor of the Guardian or the Independent, could say otherwise."

He also refused to take back his description of actor Hugh Grant's allegations about phone hacking at the Mail as "mendacious smears driven by his hatred of the media", unless Mr Grant withdrew his statement.

Jay citing Guardian journo Nick Davies saying clarifications are smaller than stories, saying complainants are worn down by war of attrition

Defending a Mail story reporting the birth of Mr Grant's baby, he said a newspaper was entitled to ask a celebrity such as Grant if he had had a child, especially when he had spoken previously of his desire to be a father.

"Mr Grant has spent his life invading his own privacy," he said. "It seems a little bit ripe that when he does have a child, he and his press representatives won't confirm or deny that."

Last October, ahead of the start of the inquiry, Mr Dacre delivered a seminar in which he argued self-regulation was the "only viable way" of policing a free press.

During an afternoon of questioning at the inquiry, he was asked to outline his views on how the current system could be improved.

He suggested the industry could benefit from another body - on top of the Press Complaints Commission - to deal with standards, such as an ombudsman.

Another idea was for a new press card system - existing cards "don't mean much", he said.

Only journalists on papers signed up to the PCC could be entitled to them, and any without them could be refused access to government briefings or royal events.

The ombudsman, he suggested, could have the power to cancel the card of a journalist guilty of gross malfeasance, just as doctors are struck off.

Mr Dacre also suggested picture agencies should join the new body and sign up to the code of practice.

Other details to emerge included:

Mr Dacre's "pity" that the News of the World had closed. "I wouldn't have had the News of the World in my house but it did break great, great stories ... (with) a lot of serious political coverage in it," he said.

Questioning about Jan Moir's article on the death of gay BoyZone singer Stephen Gately, Mr Dacre said: "There isn't a homophobic bone in Jan Moir's body. I would die in a ditch to defend any of my columnists' right to write what they wish."

Standards slipped in the coverage of Chris Jefferies, the landlord of Jo Yeates who was arrested but never charged on suspicion of her murder, Mr Dacre said. "I apologise to Mr Jefferies," he said, claiming that the Daily Mail was one of the least worst offenders.

Mr Dacre dismissed a suggestion that the Mail's campaign over murdered Stephen Lawrence came about after the London teenager's father did some plastering work for him. "I really do find that insulting," he said.

Police investigations

During the morning session, the inquiry heard from the Metropolitan Police, which believes 829 people were "likely" victims of phone-hacking by newspapers.

Deputy Assistant Commissioner Sue Akers confirmed that 581 of those had been contacted, but 231 could not be identified and 17 had not been told for "operational reasons".

She is overseeing three investigations involving claims of newspaper hacking.

Ninety police staff are involved in Operation Weeting, which is investigating allegations of hacking by News of the World into private voicemails.

So far, Ms Akers said, 17 people had been arrested - two had been released without any action, and the remaining 15 were due to answer bail in March.

A further 40 police officers and staff are working on Operation Elveden, looking at allegations that journalists from News International (owner of the now-defunct News of the World) made "inappropriate" payments to police.

A third investigation - Operation Tuleta - is investigating computer hacking, and involves about 20 officers.